The invention relates to a filter cartridge, in particular for an intake air filter of an internal combustion machine.
A filter cartridge of this type is described in DE 88 05 049 U1. Such filter cartridges, however, have the disadvantage that the outer margin of the supporting and sealing ring can slip from the filter paper web in cases of extreme stress, since only a force locking connection is present. At that point a direct connection between the raw air inlet and the clean air outlet results; the flow cross-section of which is indeed small, but which can result in disturbances or an increased wear and tear of the internal combustion machine which is arranged downstream.
DE-OS 27 38 086 shows a filter cartridge which is composed of a filter material and a flange piece which is molded onto it and which is made of a moldable, Curable material, e.g. synthetic resin or rubber, which remains flexible after curing. The end region of the filter material is embedded in the flange material. In order to create a more secure bond, it is proposed that the filter material be equipped with a perforation such that the fluid material flows through the holes in the filter material while the flange piece is being cast and such that a peg connection is established between the filter material and the flange material.
In this known filter cartridge, it is considered disadvantageous that a casting mold is needed to cast the flange piece, a fact which, together with the relatively slow curing process, results in a long cycle time and therefore yields a low productivity.
Another disadvantage also lies in the fact that the body of the filter paper has to be provided with a perforation which must be produced in an additional processing step and which in the event of an incomplete casting also produces a short circuit between the raw air side and the clean air side.
Furthermore, a filter cartridge which has an end disk made of a sealing material is known from DE 38 38 540. This end disk is bonded to the filter paper body by means of a special adhesive. In addition, the end disk is designed such that a serration arises between the adhesive and end disk. However, the resulting disadvantage can now be observed in the fact that the end disk is a part which is complicated and costly to manufacture.
A further problem when using a filter cartridge for the intake air of an internal combustion machine lies in the fact that the seal--regardless of what form it takes--must exhibit an ideally long-term durability, i.e., that even with the long service intervals which are usual for motor vehicles, it must be assured that neither embrittlement nor cracks arise and that a certain permanent set remains intact which guarantees a good scaling behavior over a long period of time.